1. Field of the Invention
The present invention relates to a hold-response type display device such as a liquid crystal display, an organic EL (Electro Luminescence) display, an LCOS (Liquid Crystal On Silicon) display, and more particularly to a display device which is applicable to a display of motion pictures.
2. Description of the Related Art
Conventionally, in classifying a display from a viewpoint of a motion picture display, the display is roughly classified into an impulse-response-type display and a hold-response-type display. The impulse-response-type display is, for example, a display of a type in which the luminance response is lowered directly after scanning as in the case of a residual light characteristic of a cathode ray tube. Further, the hold-response-type display is, for example, a display of a type in which the luminance based on display data is held until next scanning as in the case of a liquid crystal display.
The hold-response type display can obtain a favorable display quality without generating flickers when a still picture is displayed. However, when the hold-response type display displays motion pictures, there exists a drawback that, so-called motion picture blurring in which a periphery of a moving object is blurred occurs so that the display quality is remarkably lowered. The generation of the motion picture blurring is caused by a so-called image retention on retina in which, when a line of sight moves along with the movement of the object, an observer interpolates display images before and after the movement with respect to a display image with which the luminance is fixed. Therefore, in the hold-response type display, even when an attempt to increase a response speed to maximum is made, it is impossible to completely eliminate the motion picture blurring. Accordingly, there has been proposed a method in which, in the hold-response type display, for example, by updating the display image with a shorter frequency, or by canceling the image retention on retina by inserting a black screen or the like, the hold-response type display is allowed to approach the impulse-response type display whereby the motion picture blurring is reduced.
A typical display which requires the motion picture display is a television receiver set, and a scanning frequency of the television receiver set is standardized in such a manner that the scanning frequency of NTSC type television receiver set is interlaced scanning of 60 Hz and the scanning frequency of PAL type television receiver set is sequential scanning of 50 Hz. When a frame frequency of a display image which is generated based on the scanning frequency is set to 60 Hz or 50 Hz, the frequency is not increased and hence, the motion picture blurring is generated.
To reduce the motion picture blurring in the television receiver set, as a technique which updates display image with the shorter frequency as mentioned above, there has been proposed a technique in which a scanning frequency is increased and, at the same time, display data of an interpolation frame is generated based on display data between frames thus enhancing an updating speed of the image (hereinafter, abbreviated as an interpolation frame generation method) (for example, see patent document 1).
Further, as a technique which inserts the black screen (the black frame) as mentioned above, for example, there has been proposed a method which inserts black display data between display data (hereinafter, abbreviated as a black display data inserting method) (for example, see patent document 2).
Patent document 1: JP-A-2005-6275 (related US2004/101058)
Patent document 2: JP-A-2003-280599 (related US2004/0001054)